The present invention relates generally to agricultural harvesters such as combines, and more particularly to the drive systems associated with header and feed mechanisms for supplying crop material into the machine for processing, and still more particularly to reverse drive systems that can be activated for backing out crop material when overfeeding or clogging conditions are present, or to otherwise withdraw material from the feed mechanism.
An agricultural harvester known as a “combine” is termed as such historically because it combines multiple harvesting functions, such as picking or cutting, threshing, separating and cleaning in a single harvesting machine. A typical combine includes a header which removes the crop from a field, and a feeder which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves, and performs a threshing operation on the crop, to dislodge the grain from other crop material. Once the grain is threshed, it falls through perforations in the threshing concaves onto a grain pan. From the grain pan, the grain is cleaned on sieves in a cleaning system. A cleaning fan blows air through the sieves to discharge chaff and other debris toward the rear of the combine. Non-grain crop material, such as straw from the threshing system, proceeds through a residue system, which may utilize a straw chopper to process the non-grain material and direct it out the rear of the combine. The cleaned grain is transported to a grain tank onboard the combine. When the grain tank becomes full or is to be emptied for other reasons, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, gravity box, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain from the grain tank into the vehicle.
More particularly, a header can include a cutter bar or other mechanism to sever or remove crop material from the field, and a reel, conveyors, augers and/or other transport devices that gather and direct the cut crop material to feed downstream processing systems in the machine. It is known to cut a wide swath of crop and then to gather the crop inwardly toward the center of the machine from the outer edges, to thereby concentrate the crop stream as it enters subsequent processing systems. Such downstream processing systems can include a rotary threshing or separating system having one or more rotors which can extend axially (front to rear) or transversely (side to side) within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the threshing concave. Coarser non-grain crop materials, such as stalks and leaves, are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop materials such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to the cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.
The cleaning system further separates the grain from non-grain crop material, and typically includes a fan directing an airflow stream upwardly and rearwardly through vertically arranged sieves, with the sieves oscillating in a fore and aft manner. The airflow stream lifts and carries the lighter non-grain crop material towards the rear end of the combine for discharge to the field. Clean grain, being heavier, and larger pieces of non-grain crop material, which are not carried away by the airflow stream, fall onto a surface of an upper sieve (also known as a chaffer sieve) where some or all of the clean grain passes through to a lower sieve (also known as a cleaning sieve). Grain and non-grain crop material remaining on the upper and lower sieves are physically separated by the reciprocating action of the sieves as the material moves through the combine. Any grain and/or non-grain crop material remaining on the top surface of the upper sieve is discharged at the rear of the combine. Grain falling through the lower sieve lands on a bottom pan of the cleaning system, where it is conveyed toward a clean grain auger. The clean grain auger conveys the grain to the onboard grain tank for temporary storage.
During normal operation of a harvesting machine, the onboard engine powers the various systems, including the crop infeed systems, through mechanical drive line connections. For example, through the use of various shafts, belt drives, chain drives and the like, several augers, conveyors or other mechanisms of the header and infeed systems can be driven in unison. Under some operating conditions, crop material can clump or bunch, forming a potential clog that can interrupt continued performance, or even plug the machine. To prevent or eliminate this condition, the crop material can be moved backwards from its normal travel direction to remove, reposition or redistribute the clump of material. It is impractical and undesirable to reverse the entire drive system, so it is known to use separate reversing drive motors to reverse drive more limited groupings of the mechanisms. The main or forward drive is interrupted, and the reversing drive is operated. However, to integrate the reversing drive motor into the drive line can be difficult, complicated and costly. A hydraulic motor with an appropriate clutch for engagement to and disengagement from the drive line can require significant space in the machine and the various parts therefore can be expensive. Complex systems can be difficult and expensive to repair and maintain.
What is needed in the art is a reversing system drive arrangement that is compact and simple in operation and use, for selectively decoupling the primary drive system and coupling the reversing system when needed.